Hematopoietic stem and progenitor cells regulate the regeneration of their niche by secreting Angiopoietin-1

BO Zhou, L Ding, SJ Morrison - Elife, 2015 - elifesciences.org
BO Zhou, L Ding, SJ Morrison
Elife, 2015elifesciences.org
Hematopoietic stem cells (HSCs) are maintained by a perivascular niche in bone marrow
but it is unclear whether the niche is reciprocally regulated by HSCs. Here, we systematically
assessed the expression and function of Angiopoietin-1 (Angpt1) in bone marrow. Angpt1
was not expressed by osteoblasts. Angpt1 was most highly expressed by HSCs, and at
lower levels by c-kit+ hematopoietic progenitors, megakaryocytes, and Leptin Receptor+
(LepR+) stromal cells. Global conditional deletion of Angpt1, or deletion from osteoblasts …
Hematopoietic stem cells (HSCs) are maintained by a perivascular niche in bone marrow but it is unclear whether the niche is reciprocally regulated by HSCs. Here, we systematically assessed the expression and function of Angiopoietin-1 (Angpt1) in bone marrow. Angpt1 was not expressed by osteoblasts. Angpt1 was most highly expressed by HSCs, and at lower levels by c-kit+ hematopoietic progenitors, megakaryocytes, and Leptin Receptor+ (LepR+) stromal cells. Global conditional deletion of Angpt1, or deletion from osteoblasts, LepR+ cells, Nes-cre-expressing cells, megakaryocytes, endothelial cells or hematopoietic cells in normal mice did not affect hematopoiesis, HSC maintenance, or HSC quiescence. Deletion of Angpt1 from hematopoietic cells and LepR+ cells had little effect on vasculature or HSC frequency under steady-state conditions but accelerated vascular and hematopoietic recovery after irradiation while increasing vascular leakiness. Hematopoietic stem/progenitor cells and LepR+ stromal cells regulate niche regeneration by secreting Angpt1, reducing vascular leakiness but slowing niche recovery.
DOI: http://dx.doi.org/10.7554/eLife.05521.001
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